mmapped_buffer.cpp revision 88bc312ad34321fb3e81be2dc939a889d065f4a7 
1/*
2 * Copyright (C) 2013, The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "dictionary/utils/mmapped_buffer.h"
18
19#include <cerrno>
20#include <climits>
21#include <cstdio>
22#include <fcntl.h>
23#include <sys/mman.h>
24#include <unistd.h>
25
26#include "dictionary/utils/file_utils.h"
27
28namespace latinime {
29
30/* static */ MmappedBuffer::MmappedBufferPtr MmappedBuffer::openBuffer(
31        const char *const path, const int bufferOffset, const int bufferSize,
32        const bool isUpdatable) {
33    const int mmapFd = open(path, O_RDONLY);
34    if (mmapFd < 0) {
35        AKLOGE("DICT: Can't open the source. path=%s errno=%d", path, errno);
36        return nullptr;
37    }
38    const int pagesize = sysconf(_SC_PAGESIZE);
39    const int offset = bufferOffset % pagesize;
40    int alignedOffset = bufferOffset - offset;
41    int alignedSize = bufferSize + offset;
42    const int protMode = isUpdatable ? PROT_READ | PROT_WRITE : PROT_READ;
43    void *const mmappedBuffer = mmap(0, alignedSize, protMode, MAP_PRIVATE, mmapFd,
44            alignedOffset);
45    if (mmappedBuffer == MAP_FAILED) {
46        AKLOGE("DICT: Can't mmap dictionary. errno=%d", errno);
47        close(mmapFd);
48        return nullptr;
49    }
50    uint8_t *const buffer = static_cast<uint8_t *>(mmappedBuffer) + offset;
51    if (!buffer) {
52        AKLOGE("DICT: buffer is null");
53        close(mmapFd);
54        return nullptr;
55    }
56    return MmappedBufferPtr(new MmappedBuffer(buffer, bufferSize, mmappedBuffer, alignedSize,
57            mmapFd, isUpdatable));
58}
59
60/* static */ MmappedBuffer::MmappedBufferPtr MmappedBuffer::openBuffer(
61        const char *const path, const bool isUpdatable) {
62    const int fileSize = FileUtils::getFileSize(path);
63    if (fileSize == -1) {
64        return nullptr;
65    } else if (fileSize == 0) {
66        return MmappedBufferPtr(new MmappedBuffer(isUpdatable));
67    } else {
68        return openBuffer(path, 0 /* bufferOffset */, fileSize, isUpdatable);
69    }
70}
71
72/* static */ MmappedBuffer::MmappedBufferPtr MmappedBuffer::openBuffer(
73        const char *const dirPath, const char *const fileName, const bool isUpdatable) {
74    const int filePathBufferSize = PATH_MAX + 1 /* terminator */;
75    char filePath[filePathBufferSize];
76    const int filePathLength = snprintf(filePath, filePathBufferSize, "%s%s", dirPath,
77            fileName);
78    if (filePathLength >= filePathBufferSize) {
79        return nullptr;
80    }
81    return openBuffer(filePath, isUpdatable);
82}
83
84MmappedBuffer::~MmappedBuffer() {
85    if (mAlignedSize == 0) {
86        return;
87    }
88    int ret = munmap(mMmappedBuffer, mAlignedSize);
89    if (ret != 0) {
90        AKLOGE("DICT: Failure in munmap. ret=%d errno=%d", ret, errno);
91    }
92    ret = close(mMmapFd);
93    if (ret != 0) {
94        AKLOGE("DICT: Failure in close. ret=%d errno=%d", ret, errno);
95    }
96}
97
98} // namespace latinime
99